Night shift women with significantly increased cancer risk

Nocturnal work has an effect on the development of cancer?

Researchers found that when women work in night shifts, it significantly increases the risk of some forms of cancer. Especially skin cancer, breast cancer and gastrointestinal cancers are particularly affected by the effects of nocturnal work.

Researchers from Sichuan University in China found in their recent research that night-shift women are at increased risk for cancer. The researchers arrived at this result in a so-called meta-analysis with the data from a total of 61 medical studies. The researchers published the results of their submission in the English-language journal "Cancer Epidemiology, Biomarkers & Prevention".

Working regularly on the night shift increases the risk of developing various forms of cancer. (Image: Tanja / fotolia.com)

How does work at night affect the risk of breast cancer??

In most countries around the world, breast cancer is the most commonly diagnosed form of cancer, explains author Xuelei Ma. There have been several previous meta-analyzes that have focused on understanding the relationship between night shift work and breast cancer risk. However, the conclusions of these analyzes were inconsistent.

Investigations included nearly 4 million subjects

The experts looked at how long-term night-shift work in women affects the risk of different cancers. For this they performed a meta-analysis with data from 61 different scientific articles. These included 3,909,152 participants from North America, Europe, Australia and Asia. Overall, the subjects had 114,628 cases of cancer.

One analysis looked only at the cancer risk of nurses

The reviewed articles consisted of 26 cohort studies, 24 case-control studies, and 11 nested case-control studies. All of these studies looked at a relationship between long-term night shift work and the risk of eleven different forms of cancer. In addition, a further analysis was conducted specifically on long-term night shift work and the associated risk of six types of female nurse cancer.

How strongly was the cancer risk increased by the night work?

Overall, long-term night shift work among women increased cancer risk by 19 percent, say the authors. The night shift work affected various forms of cancer. For example, the increased risk of breast cancer was 32 percent, skin cancer 41 percent, and gastrointestinal cancer increased the risk of long-term night shift work by 18 percent, compared to women who did not work long-term night shift.

Increased breast cancer risk from night shift work detected only in North America and Europe

The researchers also found that there was an increased risk of breast cancer only for female night shift workers in North America and Europe. "We were surprised to see the correlation between night shift work and breast cancer risk only in women in North America and Europe," explains Xuelei Ma. It is possible that women in these areas have a higher sex hormone level, which affects hormone-related cancers such as breast cancer, the expert adds.

Nurses working in the open are particularly likely to develop breast cancer

For female nurses working night shifts, the risk of breast cancer increased by 58 percent and lung cancer by 28 percent compared to non-night shift nurses, the researchers report. Of all the occupations analyzed, nurses were at the highest risk of developing breast cancer when working on the night shift. Nurses working at night have a background in medical science and are more likely to undergo screening, explains Xuelei Ma. Another possible explanation for the identified increased cancer risk among these women may be related to the night-shift-care workplace requirements, such as more intense shifts, the expert adds.

Long-term night shift workers should be checked regularly

The physicians explained that the risk of developing breast cancer from work in the night shift increases by 3.3 percent every five years. "By systematically integrating a wealth of past data, we found that night shift work is associated with an increased risk of multiple common types of cancer in women," say the experts. The results of this study indicate the need for health programs for long-term workers in the night shift sector, the authors add. Long-term night shift workers should have regular preventive check-ups for safety's sake. (As)